Copper welding
Success factors for laser welding copper
Powerful lasers, specific laser equipment with special optics systems and many years of experience in parameter determination are essential prerequisites for laser steel welding of copper (Cu). BLS Lasertechnology GmbH supports you with extensive laser know-how from parameter determination and basic development to prototype production and series production. Our experienced laser specialists and welding engineers ensure optimum overall results in copper welding, which can be efficiently implemented thanks to our in-house fixture construction and innovative laser equipment.
Copper welding
(copper laser welding)
For BLS customers, the processing of copper components using laser technology is particularly relevant for current-conducting workpieces in e-mobility (battery systems, battery modules) or for other areas of electronics (connectors, stranded wires, circuit boards). In the laser beam welding process, copper differs from other metals due to its specific material properties, such as its very good electrical and thermal conductivity and high reflectivity in the infrared range.
In principle, copper (pure copper and copper alloys) can be welded using all common laser welding techniques. However, the right choice of process and precise adjustment of the parameters adapted to the material are essential when welding copper. Coupling the laser beam can be a challenge due to the low absorption of the laser radiation in the copper metal, as the optimum “processing window” for the molten copper produced by the laser beam is narrow.
Copper welding with innovative process technology
Laser welding copper requires a process technology that is adapted to the material. Depending on the condition of the components, it may be necessary to thoroughly clean the surfaces beforehand, either by brushing, milling and grinding or by chemically removing (pickling) the oxide layer. Preheating the material before the welding process facilitates the formation of the molten copper by the laser beam, prevents deformation and results in more stable weld seams overall.
The optimum process parameters must always be individually determined and fine-tuned when laser welding copper or copper alloys. In particular, the use of special optics is a success factor for high weld seam quality. BLS Lasertechnology GmbH has extensive experience in copper welding from a large number of customer projects in the field of battery and battery module development as well as current-carrying components.
Laser welding of copper and aluminum in comparison
Copper is characterized by its high thermal conductivity and surface reflection. The special feature of copper is its very good electrical conductivity. Laser welding copper requires an even higher laser power than aluminum welding. Due to the absorption jump during the phase transition of the metal from the solid state to the liquid melt, copper welding requires expertise and experience in determining the parameters and developing the application of the welding process.
Like copper, aluminum has a high surface reflection and good thermal conductivity. This makes energy absorption more difficult and processing requires a significantly higher laser power than for steel or iron, for example.
Copper welding: Laser welding processes at a glance
Pulse welding
Short laser pulses create spot welds. This process is suitable for thin materials, such as copper sheets, or for very precise applications.
Continuous wave welding
(“Continuous Wave”, CW)
Here, a continuous laser beam ensures continuous weld seams. The process stability is high with this method, but the welding depth remains low. Pure heat conduction welding is suitable for joining thin components, while deep penetration welding with significantly higher laser power can also be used to join thicker workpieces.
Deep welding
Deep welding of copper creates a deep vapor capillary, the “keyhole”. When the steam flows out, it exerts pressure on the molten metal and partially displaces it. This technique allows greater welding depths and slim, deep copper weld seams to be achieved.
Copper welding: Laser welding process in detail
Solid-state lasers such as Nd:YAG lasers or modern fiber lasers are suitable for laser welding copper, but electron beam or inert gas welding processes can also be used.
However, the highest energy densities are achieved with laser and electron beam welding. High welding speeds and narrow weld seams are possible with these two welding processes. The fact that only narrow heat-affected zones occur here has a positive effect on the residual stress and distortion of the processed component. An economic advantage of laser beam welding is that, in contrast to electron beam welding, no vacuum situation needs to be created, meaning that significantly shorter cycle times are possible in series production.
In laser welding with filler material (laser metal deposition), welding rods or metal powders made of similar alloys to the base material are used to ensure the best possible compatibility. Argon or an argon-helium mixture is generally used as the shielding gas to prevent oxidation and control the formation of plasma above the molten metal.
For flat copper components, in addition to laser welding technology, pure inert gas welding processes can also be used for certain applications, such as TIG welding (sheet thicknesses < 10 mm) or MIG welding (thicker sheets) of copper. Helium, argon or their mixtures are also used as shielding gases. – However, these two welding techniques do not count as laser beam welding processes!
Reference projects BLS in copper welding
- Busbar welds as part of battery module development for a leading e-mobility automotive customer
- Determination of welding parameters for a new battery generation for a leading battery manufacturer, including welding of initial samples with sharp cells in the high-voltage range
- Series production of busbars with aluminum-copper connections for an international manufacturer of energy storage systems
BLS success factors for the laser welding of copper
We are happy to advise you at!
BLS Lasertechnology GmbH has all common laser welding processes at its disposal. We will be happy to advise you on the selection of the right process, taking into account the requirements of the weld seam and the component to be processed. The focus is always on quality and an optimum result. Contact us and together we will find a solution to your problem!
